The present invention relates to a slide mounter for preparing photographic slides for use with a slide projector. More specifically, the invention relates to an apparatus incorporated in a slide mounter for severing film transparencies from a photographic film web for insertion into a slide mount.
Automatic and semi-automatic slide mounters continuously sever individual film transparencies from a photographic film web to insert film transparencies into slide mounts to prepare photographic slides. I n semi-automatic and automatic slide mounters, the film web is mechanically advanced through a series of operations to sever a leading film transparencies from the film web to prepare photographic slides. It is important in such operation to align the trailing edge of the leading film transparency with a knife assembly (used to sever the film transparencies) so that the film transparency is properly severed from the photographic film web. If the trailing edge of the film transparency is not correctly aligned, the photographic slide prepared will not contain the entire image of the exposed film transparency. Alternatively, if not correctly aligned, the photographic slide prepared may contain the images of consecutive film transparencies.
Typically, the film web is supported along a film path. The film web is advanced along the path in steps (or advancement strokes) to position consecutive film transparencies (the leading film transparency each time) with the knife assembly for operation. The extent of the advancement stroke is defined by the distance between the knife assembly and the trailing edge of the leading film transparency. That is, the leading film transparency must be advanced so that the trailing edge thereof is positioned across blades of the knife assembly for operation. If the trailing edge of the leading film transparency is not correctly aligned initially, the advancement stroke may not correctly position the film transparency with the blades of the knife assembly. For example, if the distance from the trailing edge of the leading film transparency to the knife blade assembly is larger than the extent of the advancement stroke, the film transparency will not be correctly severed. Alternatively, if the distance from the trailing edge of the leading film transparency and the knife assembly is smaller than the advancement stroke, a part of the next film transparency will be severed with the leading film transparency. Thus, it is important to adjust the film web relative to the knife assembly to assure proper placement for operation.
In the past, the film web has been physically adjusted to properly align (or finely adjust the position of) the film web with the knife assembly relative to the advancement stroke for the slide mounter. However, often times the film is still misaligned and the film is damaged or scratched as a result of repeated handling of the film to adjust the alignment thereof. Thus, there has been a continuing need to provide an apparatus for use in an automatic or semi-automatic slide mounter which will properly sever each film transparency from the film web and which will not damage or scratch the film.